Apparatus and method for multi-station conferencing

ABSTRACT

A system and method for multi-media half-duplex conferencing in a computer network comprising a plurality of stations and a control server. The method and system include, respectively, means for and the steps of receiving a packet at the server from one station of the plurality of stations including a digital representation of information of at least one information type selected from audio information and video Information, identifying the station as a transmitting station, blocking packets transmitted from the plurality of stations at the server except from the first transmitting station, distributing packets from the transmitting station, thereby providing audio information generated by a user of the transmitting stations to users of the other stations of the plurality of stations and repeating the steps of receiving, identifying, blocking and transmitting for a different one of the plurality of station, thereby replacing the transmitting station with a different transmitting station, thereby providing the half-duplex multi-station conference.

FIELD OF THE INVENTION

[0001] The present invention relates to a method and system forhalf-duplex multimedia multi-station conferencing over a networkgenerally and more particularly to a method and system for half-duplexaudio multi-station conferencing over a network.

BACKGROUND OF THE INVENTION

[0002] Wide Area Computer Networks (WAN), in particular the INTERNETnetwork, allow users to communicate multimedia information therebetween.For Example, the Internet Phone, commercially available from VocalTecInc. of New Jersey, enable audio conferencing between two parties usingtwo computer stations connected to the INTERNET and equipped with theINTERNET PHONE™ application.

[0003] In another application, multi-station multi-media conferencing isprovided. In multi-station conferencing, a number of users employ theircomputer station in order to hold a conference. Generally speaking, twotypes of multi-station conferencing exist, namely, full-duplexconferencing in which each user may speak and hear audio information,i.e. is able to simultaneously transmit and receive voice packets, andhalf-duplex conferencing in which one station is determined to be thecurrent transmitting station at a time.

[0004] Full-duplex conferencing requires a mixing mechanism by whichvoice packets transmitted by each station are mixed in a network serverso as to avoid the need to resolve according to predetermined criteriawhich participant will be the active participant. Obviously, mixingmechanisms directed to full duplex conferencing are costly and difficultto implement and require in addition a supplemental mechanism forself-hearing cancellation, such as an echo canceling algorithm.

[0005] Half-duplex conferencing requires a mechanism which will resolvewho will be the user allowed to speak to all other at any particulartime. In prior art half-duplex and conferencing, a resolving mechanismbased on an arbitration procedure between voice packets, for example theprocedure described in U.S. Pat. No. 5,434,797 to Barris is implemented.

[0006] Another drawback associated with conferencing systems in generaland with multi-media multi-station conferencing in particular is that itis sometimes difficult for one participant to recognize who is thecurrent participant. This problem is particularly difficult inmulti-station network conferencing, such as in INTERNET multi-stationconferences where participants which are not familiar with each otherhave to recognize who is the current participant.

SUMMARY OF THE INVENTION

[0007] An object of the present invention is to provide an improvedmethod for half-duplex multi-media multi-station conferencing in acomputer network.

[0008] In a preferred embodiment the multi-station half-duplexconference is an audio conference or an audio and video conference.

[0009] A further object of the present invention is to display thecurrent active participant in a multi-station conference.

[0010] There is thus provided, in accordance with a preferred embodimentof the present invention, a method for multi-media half-duplexconferencing in a computer network which includes a plurality ofstations and a control server. The method includes the steps ofreceiving a packet at the server from one station of the plurality ofstations including a digital representation of information of at leastone information type selected from audio Information and videoinformation, identifying the station as a transmitting station, blockingpackets transmitted from the plurality of stations at the server exceptfrom the first transmitting station, distributing packets from thetransmitting station, thereby providing audio information generated by auser of the transmitting stations to users of the other stations of theplurality of stations; and repeating the steps of receiving,identifying, blocking and transmitting for a different one of theplurality of station, thereby replacing the transmitting station with adifferent transmitting station, thereby providing the half-duplexmulti-station conference.

[0011] Further, according to a preferred embodiment of the presentinvention, the step of replacing includes the steps of receiving apacket indicating an end of transmission of the representation of theinformation and receiving a packet from a different station, therebyproviding the identification of the second transmitting station.

[0012] According to an alternative embodiment, the step of replacingincludes the steps of not receiving packets from the transmittingstation for a predetermined period of time and receiving a packet fromthe second station after the predetermined period of time, therebyproviding the activation of the second transmitting station.

[0013] In accordance to a preferred embodiment of the present invention,the method also includes the step of visually Indicating to the userswhich user utilizing the station which is the transmitting station.Preferably, this step includes the steps of transmitting a packetincluding a user identification from the first station to the controlserver, adding the user Identification to a participants list of usersparticipating in the half-duplex conference, thereby providing a currentparticipants list, storing the current identification list with anindication which station Is the current transmitting user, providing theuser Identification list in the stations and displaying theidentification list including the Indication of the current transmittinguser.

[0014] Further, the step of storing preferably includes the steps ofstoring an update of the current participants list with an indicationwhich station is the current transmitting user, retrieving the update inthe stations and displaying the update including the indication of thecurrent transmitting user.

[0015] There is also provided, according to a preferred embodiment ofthe present invention, a system for multi-media half-duplex conferencingin a computer network which includes a plurality of stations and acontrol server which is capable of operating in accordance to themethods of the present invention.

[0016] There is further provided in accordance with a preferredembodiment of the present invention, a method for visually indicating toparticipants of a multi-station conference, both half-duplex andfull-duplex conferences, which participant is the current activeparticipant. The method includes the steps of providing a list ofparticipants in the multi-station conference, determining a participantas a currently active participant and indicating to other participantsof the multi-station conference who is the currently active participantor participants.

[0017] In a preferred embodiment the step of indicating includes thesteps of providing the participants list or an updated portion thereofwith an indication of the currently active participant and displayingthe identification list including the indication of the current activeparticipant or participants.

[0018] Further, according to a preferred embodiment of the presentinvention, the steps of providing the participant list and the step ofproviding are independent of the step of indicating.

[0019] There is also provided, according to a preferred embodiment ofthe present invention, a system for visually indicating to participantsof a multi-station conference, both half-duplex and full-duplex, whichparticipant is the current active participant. The system includes ahuman or automatic operator for providing a participant lists or anupdate thereof and a conference bridge server connected to first means,preferably but not limited to telephone means, for determining acurrently active participant and to second means, preferably but notlimited to computer network means, independent of the first means forproviding the visual indication of the currently active participant tothe participants of the multi-station conference.

[0020] In a preferred embodiment, the conference bridge server includesa CPU for receiving the participant lists or the update thereof, astorage unit for storing the participant lists and the updates thereofand a voice activity unit connected to the first means for detecting thecurrently active participant The CPU Is operative to provide to theparticipants list or an update thereof upon with an Indication of thecurrently active user upon detecting a currently active participant orparticipants by the voice activity unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be understood and appreciated morefully from the following detailed description taken in conjunction withthe appended drawings in which:

[0022]FIG. 1 is a schematic block diagrams of a Wide Area Network forproviding half-duplex multimedia multi-station conferencing, constructedand operative in accordance with a preferred embodiment of the presentinvention;

[0023]FIG. 2 is a schematic block diagram illustration of a resolvingmechanism for determining the current active multimedia station of thenetwork of FIG. 1;

[0024]FIG. 3 Is a schematic block diagram illustration of a preferredmethod for displaying the active participants in the multimediamulti-station conference held over the network of FIG. 1;

[0025]FIG. 4 is a schematic block diagrams of a system for providingmultistation conferencing, constructed and operative In accordance witha preferred embodiment of the present invention; and

[0026]FIG. 5 is a schematic block diagram illustration of a preferredmethod for operating the system of FIG. 4.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0027] Reference is now made to FIG. 1 which illustrates a Wide AreaNetwork (WAN), generally referenced 10, for providing half-duplexmulti-media multi-station conferencing, constructed and operative Inaccordance with a preferred embodiment of the present Invention. In apreferred embodiment, the WAN is the INTERNET.

[0028] In the preferred embodiment, WAN 10 is operative to providehalf-duplex multi-station audio conferencing and the present Inventionis described by way of a nonlimiting example with respect thereto.

[0029] WAN 10 comprises a control server 12, a plurality of multimediacomputers 14 of which four are shown as a non limiting example in theillustrated embodiment and referenced 14A, 14B, 14C and 14D. In apreferred embodiment server 12 and stations 14 are physically remote onefrom the other and are connected via the INTERNET network Multimediacomputers 14 may be any suitable multimedia computer, such as a personalcomputer equipped with an INTERNET connection and audio transceivingapplication. An example of a suitable multimedia computer 14 is thePACKARD BELL of the U.S. personal computer equipped with the INTERNETPHONE™ application. The INTERNET PHONE™ gateway application,commercially available from VocalTec Inc. of New Jersey, U.S.A, may beimplemented with any other suitable personal computer as well.

[0030] In the illustrated embodiment WAN 10 also comprises a telephonygateway 16 equipped with the INTERNET PHONE™ gateway applicationconnected to a conventional telephone and enables it to operate as oneof the WAN audio transceiving applications.

[0031] Each of stations 14 and gateway 16 comprises a voice activitydetection mechanism, such as the one incorporated in the INTERNET PHONE™which is sensitive to voice signals representing audio informationgenerated by respective users of stations 14 and telephone 18.

[0032] These transmitted voice packets are utilized to determine thecurrent speaker in the half-duplex multi-station conference as describedin detail with reference to FIG. 2 hereinbelow.

[0033]FIG. 2 illustrates a preferred method of operating themulti-station multi-media conference by server 12. First, a step ofinitialization takes place. In this step, parameters such as the maximalnumber of participants can be determined. Participants from stations 14and telephone 18 may now connect to the half-duplex conference. In step21, server 12 receives a packet or packets from a first station, say 14Aof the plurality of stations 14. The packet or packets indicate thebeginning of information transmission in at least one type of media. Inthe preferred embodiment server 12 receives audio packets indicating thebeginning of a speech burst in the format provided by the INTERNETPHONE™.

[0034] In step 22, server 12 identifies station 14A as the currenttransmitting station. Therefore, as indicated in step 23, server 12 willblock packets from all other stations 14 and telephony gateway 16 andwill continue to receive packets from current transmitting station 14A.

[0035] Each received packet is generally immediately distributed asindicated by step 24 to stations 14B-14D and telephone 18 via gateway16, thereby providing audio information generated by the user employingstation 14A.

[0036] Server 12 replaces the current transmitting station with adifferent one as indicated by steps 25 and 26 as follows. In oneoperation mode, server 12 receives an end of information packetindicating that no further packets are expected from station 14A.Alternatively, or in addition thereto, server 12 detects an interruptionfor a time period which is longer than a predetermined time. A preferredInterruption time is one second. In either case, if a packetrepresenting an end of speech burst is received or if the predeterminedtime threshold is exceeded without receiving a packet, server 12 ceasesthe identification of station 14A as the current transmitting stationand expects to receive a packet from any second station which will beset as the active station.

[0037] If a packet is received from a second station, say telephone 18via gateway 16, the user utilizing telephone 18 becomes the currentspeaker and telephone 18 becomes the current transmitting station.Similarly, any of stations 14 may become the current transmittingstation.

[0038] It will be appreciated that the method of FIG. 2 is moreefficient and cost effective with respect to prior art conferencingmethods. Since the method of the present invention provides half-duplexconferencing, it does not require complex mixing nor an echo cancelingalgorithm. Furthermore, according to the method of FIG. 2 each station14 receives only a single stream of information representing theinformation addressed by the current active participant, therefore itrequires less data handling and utilizes more efficiently existinghardware and network bandwidth.

[0039] Moreover, since the method of the present invention is mediainsensitive, i.e. It does not require any determination of the type ofmedia transmitted, it is applicable to any multi-media informationwhether visual, graphic, midi or audio as described in the preferredembodiment or any combination therebetween.

[0040] Reference is now made to FIG. 3 which illustrates a method forindicating to the users of stations 12 and telephone 18 a useridentification of the user utilizing the station which is the currenttransmitting station.

[0041] At step 31 a user which did not participate before in themulti-station conference is joining the conference. Step 31 is obviouslyrequired only if a new user is joining the conference. Similarly, instep 32 if a new user joins, the name is added to an identification listof the participants in the multi-station conferencing. Otherwise, themethod starts at step 33.

[0042] Step 33 includes the step of transmitting a packet including auser identification from the transmitting station, say 14A to controlserver 12. In step 34, the current user identification is added to theIdentification list of users participating is the conference stored inserver 12.

[0043] The updated list is then retrieved by or transmitted to eachstation 14 and gateway 16 in its entirety as indicated by 35 or only anupdated version thereof as indicated by step 36. Finally, as indicatedby 37 the updated list or the entire list of participant with thecurrent user identification highlighted is displayed.

[0044] It will be appreciated that the display in stations 14 is done onthe computer display whereas similar display with respect to telephone18 requires an internal display or a different display havingindependent connection to WAN 10.

[0045] It will be appreciated that while the present invention is notlimited by what has been described hereinabove and that numerousmodifications, all of which fall within the scope of the presentinvention, exist. For example, while the present invention has beendescribed with reference to half-duplex multi-station audioconferencing, the method and system of the present invention is notlimited thereto and is similarly applicable to video half-duplexmulti-station conferencing.

[0046] Another example described with reference to FIGS. 4 and 5hereinbelow is to display to participants of any multi-stationconference the current speaker or speakers.

[0047]FIG. 4 illustrates a non limiting example of a telephonymulti-telephone conference. The system comprises a conference bridgeserver 40 having two connection channels to each participant, atelephony channel indicated by lines 41 which includes a voice activitydetection unit 42 and connected to a telephone 43 for each user, and adisplay channel 43 connected to display units 44 for each user.

[0048] Telephony units 43 and display units 44 may be separated andoperative on difference physical networks, a non limiting example beingthe conventional telephony network and the INTERNET, respectively or maybe lumped as shown for the unit referenced 45. For the INTERNET example,displays 44 may be similar to stations 14.

[0049] A preferred operation mode of the system of FIG. 4 is describednow with reference to FIG. 5. In step 50, the operator 46, a humanoperator or an automatic telephony operator acquires the details of theparticipants in the conference. In step 51, the network identificationassociated with each participant is transmitted as a participants listto the conference bridge server 12 which stores a current participantlist at storage unit 47.

[0050] It will be appreciated that steps 50 and 51 are repeated for eachnew participant joining the conference, i.e. the operator 46 updates theparticipant lists and provide same to CPU 47 of server 40 for storing Instorage unit 48.

[0051] The conference now begins and voice activation units 42 detect acurrent active user or users and provide same to CPU 47 which updatesparticipant list stored in storage unit 48 with a current active speakeror speakers as indicated by step 52.

[0052] Each participant can now connect to server 40 using its displaysystem for retrieving the current updated list of participants with theactive participant or participants, i.e. the current speaker or speakersfor display on his own display 44.

[0053] Alternatively, Displays 44 are continuously connected to server40 and server 40 periodically transmits an updated list of participantswith the current active participants to each of displays 44.

[0054] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present invention isdefined only by the claims that follow:

1. A method for multi-media half-duplex conferencing in a computernetwork comprising a plurality of stations and a control server, themethod comprising the steps of; receiving a packet at said server fromone station of said plurality of stations including a digitalrepresentation of information of at least one information type selectedfrom audio information and video information: identifying said stationas a transmitting station; blocking packets transmitted from saidplurality of stations at said server except from said first transmittingstation; distributing packets from said transmitting station, therebyproviding audio information generated by a user of said transmittingstations to users of the other stations of said plurality of stations;and repeating said steps of receiving, identifying, blocking andtransmitting for a different one of said plurality of station, therebyreplacing said transmitting station with a different transmittingstation, thereby providing said half-duplex multi-station conference. 2.A method according to claim 1 wherein said step of replacing comprisesthe steps of receiving a packet indicating an end of transmission ofsaid representation of said Information; and receiving a packet from adifferent station, thereby providing said identification of said secondtransmitting station.
 3. A method according to claim 1 wherein said stepof replacing comprises the steps of not receiving packets from saidtransmitting station for a predetermined period of time; and receiving apacket from said second station after said predetermined period of time,thereby providing said activation of said second transmitting station.4. A method according to claim 1 and further comprising the step ofvisually indicating to said users which user utilizing the station whichis said transmitting station.
 5. A method according to claim 4 whereinsaid step of indicating comprising the steps of: transmitting a packetincluding a user Identification from said first station to said controlserver; adding said user identification to a participants list of usersparticipating is said half-duplex conference, thereby providing acurrent participants list; storing said current identification list withan indication which station is the current transmitting user; providingsaid user identification list in said stations; and displaying saididentification list including said indication of said currenttransmitting user.
 6. A method according to claim 5 wherein said step ofstoring comprises the steps of: storing an update of said currentparticipants list with an indication which station is the currenttransmitting user; retrieving said update in said stations; anddisplaying said update including said indication of said currenttransmitting user.
 7. A method for visually indicating to participantsof a multi-station conference, which participant is the current activeparticipant, the method comprising the steps of: providing a list ofparticipants in said multi-station conference; determining a participantas a currently active participant; and indicating to other participantsof said multi-station conference who is the currently active participantor participants.
 8. A method according to claim 7 wherein said step ofindicating comprising the steps of: providing said participants list oran updated portion thereof with an indication of the currently activeparticipant; and displaying said identification list including saidindication of said current active participant or participants.
 9. Amethod according to claim 7 wherein said steps of providing saidparticipant list and said step of providing are independent of said stepof indicating.
 10. A method according to claim 7 wherein said conferenceis a half-duplex multi-station conference or a full-duplex multi-stationconference.
 11. A system for multi-media half-duplex conferencing in acomputer network comprising a plurality of stations and a control servercomprising: means for receiving a packet at said server from one stationof said plurality of stations including a digital representation ofinformation of at least one information type selected from audioinformation and video information; means for activating said station asa transmitting station; means for blocking packets from said pluralityof stations except from said first transmitting station; means fordistributing packets from said transmitting station, thereby providingaudio information generated by a user of said transmitting stations tousers of the other stations of said plurality of stations; and means forrepeating said steps of receiving, activating, blocking and transmittingfor a different one of said plurality of station, thereby providing saidhalf-duplex multi-station conference.
 12. A system according to claim 11wherein said means for replacing comprises means for receiving a packetindicating an end of transmission of said representation of saidinformation; and means for receiving a packet from said different one ofsaid plurality of stations, thereby providing said activation of saidsecond transmitting station.
 13. A system according to claim 11 whereinsaid means for replacing comprises means for determining non-receipt ofpackets from said transmitting station for a predetermined period oftime; and means for receiving a packet from said different one of saidplurality of stations after said predetermined period of time, therebyproviding said activation of said second transmitting station.
 14. Asystem according to claim 11 and further comprising means for visuallyindicating to said users which user utilizing the station which is saidtransmitting station.
 15. A system according to claim 14 wherein saidstep of indicating comprising the steps of: transmitting a packetincluding a user identification from said first station to said controlserver; adding said user identification to an identification list ofusers participating is said half-duplex conference, thereby providing acurrent identification list; storing said current identification listwith an indication which station is the current transmitting user;retrieving said user identification list in said stations and displayingsaid identification list including said indication of said currenttransmitting user.
 16. A system according to claim 15 wherein said meansfor storing comprises: means for storing an update of said currentidentification list with an indication which station is the currenttransmitting user; means for retrieving said update in said stations;and means for displaying said update including said indication of saidcurrent transmitting user.
 17. A system for visually indicating toparticipants of a multi-station conference, which participant is thecurrent active participant comprising: an operator for providing aparticipant lists or an update thereof; and a conference bridge serverconnected to first means for determining a currently active participantand to second means independent of said first means for providing saidvisual indication of said currently active participant to saidparticipants of said multi-station conference.
 18. A system according toclaim 17 wherein said conference bridge server comprises: a CPU forreceiving said participant lists or said update thereof; a storage unitfor storing said participant lists and said updates thereof; and a voiceactivity unit connected to said first means for detecting said currentlyactive participant, wherein said CPU is operative to provide to saidparticipants said participants list or an update thereof upon with anindication of said currently active user upon detecting a currentlyactive user by said voice activity unit.
 19. A system according to claim17 wherein said first means are telephony means and said second meansare computer network means.
 20. A system according to claim 17 whereinsaid conference is a half-duplex multi-station conference or afull-duplex multi-station conference.